high-level temperatures from daylight ascents when the daylight and 

 night-time flights at the higher levels showed close agreement. These 

 flights were included to make the high level averages more reliable. 

 The observation stations used in this cross-section were selected so 

 .as to lie as far as possible along one meridian, thus trying to avoid 

 the more serious difliculties of interpretation which have arisen with 

 most of the so-called " meridional " cross-sections that have been 

 presented up to date. It will be seen that most of the stations lie 

 within 5° of meridian 170° E., the exceptions being Bougainville 

 (15° W. of 170° E.) and Guadalcanal (10° W. of 170° E.). However, it 

 is not thought likely that this slight deviation from meridian 170° E. 

 will give rise to any fundamental differences in the final picture 

 of the temperature field along this meridian. Again, it will be evident 

 that the cross-section lies in a purely oceanic region and should be 

 relatively free from large-scale effects of continentality. One defect of 

 this section, however, is the scarcity of data south of latitude 46° S., 

 but this seems unavoidable at present. In the future it is possible that 

 the aerological observations made recently by the U.S. Navy far to the 

 south of New Zealand can be used to complete the cross-section in higher 

 latitudes. The only data at present available is the rather scanty 

 Antarctic temperature data published by A. Court in 1942(1). 



The following table 1 shows the actual dates of the material used. 

 It win be noticed that the months selected cluster closely round January 

 or February for summer and July or August for the winter cross-section, 

 but the actual data used frec^uently depend on the number of high level 

 flights in each month's records. 



Table 1 



Summer. 



Wake Island (19° N.) 

 Kwajalein Island (9° N.) . 



Tarawa Island (li° N.) . 



Bougainville Island (6° S.) j January, 1945 

 Guadalcanal Island (9|° S.) i January, 1945 



Santo (15ir° S.) 

 Vila (18° S.) 



Noumea (22° S.) 



■Norfolk (29° S.) 



Auckland (37° S:) 

 Hokitika (43° S.) 



Taieri (46° S.) . . 

 Little America (78° S. 



November, 1945 

 February, 1944 (13 km. 



and above include also 



March, 1944) 



February, 1944, 1945 (300, 

 200, 100 mb. include 

 January, 1944, 1945) 



February, 1944-1946 . . 



February, 1944-1948 . . 

 February, 1945, 19 17, 



1948 

 February, 1944, 1945 . . 

 14 observations, Januarv, 



1940 



July, 1946. 



June, 1945 (100 and 80 mb. 

 include a few daylight 

 ascents). 



June, 1945 (100, 80, 60, 

 50, 40 mb. include a few 

 comparable daylight 

 ascents) . 



June, 1944. 



June, 1945 (150 mb. and 

 higher include tempera- 

 tures for April, 1943). 



July, 1945. 



July, 1944 (13 km. include 

 June and August, 1944 ; 

 16 km. and higher in- 

 clude May-September, 

 1944). 



Augu.st, 1943, 1944 (300, 

 2'00, 100 mb. include 

 July, 1943, 1944). 



September, 1943 : August, 

 1944, 1945. 



August, 1943-1948. 



.\ugust, 1945-1948. 



August, 1944, 1945. 

 15 observations, Septem- 

 ber, 1940. 



63 



